The objectives are: To examine whether dental abnormalities, especially enamel defects, can serve as markers of maldevelopment, and whether such findings can provide information concerning timing of adverse events or exposures. The significance of the research is that: Enamel hypoplasias and other dental anomalies can offer clues as to the timing of insults or exposures that occur from the fourth month of gestation to the age of about 12 months of extrauterine life. Correlation of dental with clinical data may offer a means to explore the timing of departure from the normal course of development in a group of children with chronic motor disability of early onset and nonprogressive course (cerebral palsy, or mental retardation).